The purpose of this study is to determine how patients with brain tumors respond to the combination of the chemotherapy drugs temozolomide and BCNU, and how long their response lasts when treated with this combination. If this treatment works, it may cause your tumor to shrink and prolong your life and/or improve the quality of your life. We also want to find out what kind of side effects these drugs cause in combination and how often they occur. Patients with glioblastoma multiforme, a type of malignant glioma, must have failed treatment with surgery and radiation and may or may not have chemotherapy. Patients with anaplastic glioma must not have had postoperative treatment with radiation or chemotherapy. Patients will receive treatments every six weeks and will be followed with MRI scans for response determination.